Treatment of molten steel.



UNITED sTA'rns PATENT OFFICE,

J'OS EPH W. EICHABDS, OF SOUTH BETHLEHEM, PENNSYLVANIA.

rnnamnu'r or women STE-EL.

. it appertains to make and use the same,

' Bessemer, open-hearth, crucible or electrio-furnace steel is manufactured inthe usual way, and broughtinto thefinished condition as far'as concerns the furnace in which it' is manufactured. Before being cast into molds, while still molten, it is, in the p icticc .of'niy invention, transferred arate' elccivr' iy-heated fu cc, id ke t therein in t i incite-n condition a fidlt' time. t is then cast. r Arno the objects thus attained may be catalogued the escapeof gases, the floating up of'impurities, the fixation of evolved inipuritics by union with t 19 lining of the furnace. completion of the intimate alloying of the -ingrodients --of the steel, increased liquidity of the metal, and the exact regulation of the casting temperature. Thesc ob-. jccts are all attained withoutanyaddition of such re-ag'ents, as are usually added to 'molten steel to. oxidize de-oxidize or otherwise refine it. Such additions, for such purposes, are in the-practice of. this process relegated to the furnaces preceding the I separate electrically-heated furnace referredv to, and the latter furnace is to receive, from the formegsteel finished in these respects,

that is, as completely finished as is commercially practicable. By thus relegating the ordinary oxidizing, de-(ixidizing and refin ing operations incident to the manufacture of steel to the furnaces preceding the separate electrically-heated furnace referred to, it is possible to do the above mentioned 'op erations under mbre favorable conditions, often to operate them more cheaply, and in furnaces better arranged for their performance. This leaves to the electricallyheated furnace referred to, simply'the task of keeping the otherwise finished steel molten a suitabletime, frees it from operations to which it may be unsuited, and allows the use of atype or style offurnace free from the requirementpf suitability for performing the ordinary oxidizing, de-oxidizing or I Specification of Letters Patent. Application filed becemberi, 1910., Serial. No. 596,236.

Patented Sept; 3,

refiningvoperations; In short, this inven tion does nbt contemplate .t-reatlnentinther separate electricallylieated furnace referred to, by such additions as are usually made to oxidize, de-oxidize or refiue' stceli but its object is to attain cheaply and economically such improvement in the otherwise finished steel as is obtained by keeping it molt'en for "asuitable time in a separate electricallyheated furnace, as an immediate precedent. to the operation of casting, The type of electric furnace which I prefer to use for this purpose is the; induction furnace, although electrode or other forms ofelect-ric furnaces can be also used; The reasonfor my preference is that, not contemplating the addition-ofv agents for oxidizing,- de? oxidizing or refining the hath, the inductioh furnace is quite suited fointhe operation of my process, with the advantagemier non-v I nductien furnaces of the-savingof costof electrodes consumed.

advantage of simpler operation becausd of the absence of electrodes and the dispensing with their cost and regulation. The induction furnace also provides in general'a. more uniform heating of the-body of steel in the furnace and still further obviates any possibility of change in the composition of the steel in the furnace from the carbon of electrodes or the ash of the same? The lining of the electric furnace which} prefer to'use is that known as acid' lining, although"basicliningean 'also be used. The reason forlmy preference inthis regard is that the final step in the manufacture of steel is usually the addition ofagents to (lo-oxidize and r'efine it, as has already been explained aboi'e, and that the acid lining of my electric holding furnace is more suited to the purpose of fixing the sus- It has the further pended oxids, the products of the preced' ing oxidizing and de'oxidizing operation, than a basic lining. The time of holding or =keeping the steel molten in the said electric furnace may be varied from a few minutes to an hour, or even longer'if found necessary or desirable, but in the majority of cases one-half an hour will be found suiticient to produce such satisfactory improvement in the steel aswill justify the use of the process of this invention. This final furnace, ivhich I may term a holding furnace, and the operation a holding opera tion, .can be used', for example, either acid lined or basic lined upon othermerbasic open-hearthacid electric.

wise finished steel made by any of the following methods or combinations of methods: 1. Acid Bessemer. 2. Basic Bessemer. 3'. Acid open-hearth. 4. Basic open-hearth. 5. Acid Bessemer-acid open-hearth. 6. Acid Bessemer acid open-hearthacid electric. 7. Acid Bessemeracid openhearth-basic electric. 8. Acid Bessemerbasic open-hearth. 9. Acid Bessemer basic open-heart-hacid' electric: 10. Acid Bessemerbasic open-hearth-bas'ic electric. 11. Basic Bessemer-acid open-hearth. 12. Basic Bessemeracid open-hearthacid electric. 13. Basic Bessemeracid openhearthbasic electric. 14. Basic Bessemer-basic open-hearth. 15. Basic Bessev Basie Bessemerbasic open-hearthbasic electric. 17. Acid Bessemer.acid electric. 18. Acid Bessemerbasic electric. 19. Basic Bessemer" acid electric. 20. Basic Bessemerbasic electric. 21. Acid openhearth'-acid electric. 22. Acid openhearthbasic electric. 23. Basic openhearthacid electric. 24. Basic openhearth-basic electric. 25. Crucible. 26. Acid electric. 27. Basic electric. 28. Acid electricbasic electric. 29. Basic electricacid electric.

By finished steel, in the intent of the foregoing specification, it will be understood that I mean steel fully manufactured in the preliminary furnace treatment contemplated in so far as concerns the elimination of its deleterious impurities and which is otherwise ready for casting at the termination of v the furnace operation according to the com mercial practice. Such finished steel, molten and otherwise ready for casting, may, in addition to receiving the benefits of its soerwise ready for casting, there maintainingit in the molten state, and thereafter casting.

3. The treatment of molten steel conslsting in transferring it into an acid-lined electric furnace when finished, molten and o'therwise ready for casting, there maintaining it in the molten state, and thereafter casting.

4. The treatment of molten steel consisting in transferring it into an acidlined induction electric furnace when finished, molten and otherwise ready for casting, there maintaining it in the molten state, and thereafter casting. v

5. Thetreatment of molten steel consisting in transferring it into an electric furnace when finished, molten and otherwiseready for casting, there maintaining it in the molten state, converting it into a special alloy steel by adding alloying metal, and thereafter casting.

In testimony whereof I atfix my signature, in presence of two witnesses.

JOSEPH W. RICHARDS. Witnesses:

JOHN C. PENNIE, I VILLIAM DAVIS. 

